(1) Technical Field
The subject invention is directed toward a radial refrigerant compressor assembly for use in automotive refrigerant systems having a fluid passageway extending between the discharge chamber which operates at an elevated pressure and the suction chamber which operates at a reduced suction pressure with a valve member disposed in the passageway to control the flow of lubricant from the discharge chamber to the working elements located in the housing in the common suction chamber when the compressor assembly is cycled on and off.
(2) Description of the Prior Art
Radial compressors have long been used for the purpose of compressing a recirculated refrigerant in an automotive air conditioning application. Compressors of this type generally include substantially cylindrically shaped housings having an offset crank drive shaft centrally supported within the housing and powered from an electromagnetically clutched continuously driven pulley. The pulley, in turn, is coupled to the power take off of an automotive engine via a flexible endless driving belt as is commonly known in the art.
Radial compressors further include a plurality of pistons radially disposed within the housing and about the shaft and which reciprocate within corresponding cylinders so as to form compression chambers. A single radially disposed discharge chamber is associated with the piston cylinder arrangements for receiving the compressed refrigerant and directing it toward the compressor exhaust port. Typically, in compressors of this type, the drive shaft, counterweight, associated bearings and other working elements of the compressor are supported in the housing in the space that also serves as a suction chamber and which operates at suction pressure. Lubricant is circulated through this chamber to lubricate the working elements in the form of a fine oil mist which is entrained in the refrigerant gas. The lubricant will then adhere to and collect on the various working elements eventually drip down past the piston/cylinder arrangements and collect or pool in the discharge chamber. More specifically, and in radial compressors of this type, the lubricant tends to pool in the lowermost portion of the radial discharge chamber directly associated with the piston which is most vertically disposed within the housing and which reciprocates to the lowest point relative to the housing. In other words, the lubricant in radial compressors tends to collect in the lowest portion of the discharge chamber relative to the rest of the housing.
The lubrication of mechanical working parts housed within a radial compressor has always been a concern for design engineers. Excessive wear and heat generated by the working parts of this type of compressor can quickly erode optimum working parameters such as volumetric efficiency and can ultimately lead to seizure or other types of failure in the compressor. It is therefore important that the lubricant is adequately distributed throughout the assembly. Further, because radial compressors are especially dependent upon adequate lubrication, it is very important that oil be distributed immediately at start up of the compressor or very shortly thereafter. It is therefore desirable that a radial refrigerant compressor assembly include a mechanism which provides for the injection of lubricant directly into the working elements of the compressor just as the compressor is cycled off, or shortly thereafter, and just as the compressor is cycled on, or shortly thereafter. In this way, adequate lubrication of the working elements of the compressor can be maintained during critical operating periods.